Flashless non-recoil gun and round



April 14, 1964 L. v. S'BLACKER FLASHLESS NON-RECOIL GUN AND ROUND FiledOct. 9. 1961 2 Sheets-Sheet l April 14, 1964 v. s. BLACKER 3,128,570

FLASHLESS NON-RECOIL GUN AND ROUND Filed Oct. 9, 1961 2 Sheets-Sheet 2IQN'" 35235332 ATTORNEY United States Patent 3,128,670 FLASHLESSNON-RECOEL GUN AND ROUND Latham Valentine Stewart Blacker, Coldhayes,Liss, England Filed Get. 9, 1961, Ser. No. 143,700 2 Claims. (Cl. 89-11)This application is a continuation-in-part of my application Serial No.528,975, filed August 17, 1955, now abandoned.

The requirements to be met by a truly satisfactory antitank gun for useby infantry are very exacting. The gun must fire a projectile ofsubstantial size, for example over 3 /2 lbs., yet the gun should ifpossible be sufficiently light to be carried by one man, and arranged tobe fired from the shoulder by a prone manthat is to say it should notrequire a free-standing mounting. It follows that, even though highmuzzle velocity is not required, because the projectile will be of thehollow charge or squash head type, the muzzle energy required issubstantial, and yet recoil on the firer must, at least to a largedegree, be avoided. Attempts have been made to achieve this bydischarging rearwards from the gun either gas, or small shot, or acounter projectile.

In assessing the success of these attempts, further factors must betaken into account. One is that it is a very serious matter if aninfantryman reveals his position to the enemy. A gun which relies onrearward discharge of gas must have a large charge, to producesufficient rearward momentum of gas to counter the momentum of thesubstantial projectile. The result is the emission of smoke, and evenworse of a great flash of flame, which reveals the position of the guneven if the gun and its firer are themselves concealed. This is mostdangerous for the user and for friendly troops in the vicinity.grettable that, in the absence of anything better, various armies aretoday equipped with weapons which emit such a flash.

Furthermore a direct rearward flash is dangerous to friendly troops inrear of the gun, and direct rearward discharge of small shot or of asolid projectile is much more dangerous. No doubt for this reason theDavis gun, which discharged small shot directly rearwards, althoughproposed initially as a piece of ordnance, Was used successfully only asan aircraft weapon, around the year 1916, rearward discharge of shotbeing not considered dangerous in the air.

The Burney gun, proposed in about 1942, but never to my knowledge usedpractically, had a rear barrel inclined at an obtuse angle to a frontbarrel, the rear barrel terminating in a set of nozzles for discharge ofgas. This would in no way reduce the dangerous flash. In fact theinclination of the rear barrel was proposed solely to enable the frontbarrel to be elevated without the rear barrel striking the ground.

I have discovered that it is possible to construct a gun which can beloaded with a unitary round including a front projectile, a propellantcharge, and a rear quantity of small shot, and which will discharge thesmall shot in a direction at an obtuse angle, of the order of 150, to afront barrel. Experience with shot guns shows that if the degree ofcontraction of a choke barrel exceeds a very small amount (e.g. 0.040inch in a twelve bore gun) the shot will jam in the barrel. Consequentlyit is far from evident that a quantity of shot starting from a positionaligned with the projectile, as it necessarily is in a unitary round,can be caused to discharge at an obtuse angle. Nevertheless I attainthis by using a rear barrel which has a substantially uniform crosssection along its whole length and which has a curvilinear axis, whichis in line at its front end with the axis of the front barrel and of achamber into which the round is loaded, the chamber It is re- 03,128,670 Patented Apr. 14, 1964 and rear barrel being separable topermit loading of the round into the chamber.

Use is made of a relatively large projectile of hollow charge or squashhead type and a relatively low charge. Consequently the pressureattained within the gun is fairly low and the gun may be correspondinglylightly constructed. Moreover, contrary to what might be expected, thecurved part of the rear barrel does not become overstressed, nor does itbecome appreciably eroded internally, nor is the resistance to movementof the shot along the rear barrel so great as to be liable to break theconnection between the chamber and the rear barrel. Any tendency toelastic deformation of the rear barrel, tending to straighten it duringfiring, is slight, and can be compensated for in the setting of thesights of the gun.

Since the projectile is relatively large, and" the maximum range atwhich a tank requires to be engaged is of the order of 1,500 to 2,000yards, the trajectory of the projectile is nearly flat. A flat latterpart of the trajectory is of importance to an infantryman, because itmakes accurate estimation of the range of a target unnecessary.Particularly good results as to flatness of trajectory and lowness ofmaximum internal pressure in the gun are obtained with an unrifled frontbarrel and a projectile of good streamline shape having a tail with adrum-type stabiliser, or radial fins which are radially movable so as tofit within the barrel on firing, but to expand to a greater radius assoon as the round has left the gun.

The lowness of the maximum. internal pressure, and the fact that the gasevolved by the charge can be sealed between a gas check in rear of theprojectile and a gas check in front of the small shot, means that thecharge is very small as compared with that for guns which discharge gasrearwards, and the smoke and flash emitted are very slight andpractically imperceptible.

With a flat trajectory, the gun is fired with the front barrel nearlyhorizontal, and consequently the shot is discharged obliquely upwardsand rearwards at about 30 to the ground. It follows a curved trajectoryupwards and then downwards, and encounters such great air resistancethat it disperses and reaches the ground at non-lethal velocity.Consequently there is only a very small area immediately in rear of thegun that is dangerous to friendly troops.

In order to assist the maintenance of uniform muzzle velocity withsuccessive projectiles, the two gas checks may be connected by a tie sothat on firing there is confinement of the charge until the tie isbroken by a substantial rise in gas pressure.

The accompanying drawings show an example of a gun and round accordingto the invention. In these drawings:

FIGURE 1 is a longitudinal section of the gun, loaded with a round;

FIGURE 2 is a longitudinal section of part of the gun and round on alarger scale.

The gun includes a straight front barrel 2 and chamber 4 in one piece,the bore of the chamber being slightly greater than that of the frontbarrel, together with a rear barrel 6 which is curved in the part of itslength nearest the chamber, through an arc of about 30, and possiblystiffened by a web 7. The rear barrel is supported by a leg 8 and a foot10, and is steadied and aimed by a prone man by means of a shoulderpiece 12 and a handle 14.

The outer straight ends 15 and 17 of the front and rear barrels can beunscrewed to reduce the bulk of the gun for carriage.

The projectile 1 consists of a head 16, tubular tail 18, and drum orcuff type stabilizer 20 on the end of the tail, and is driven by a gascheck 22 having a spigot 24 which fits into the tail and which isjettisoned by a small charge 23 after the projectile leaves the gun. Asafety collar 25 is in fact removed before loading. A quantity of smallshot 26 is housed in a thin metal casing 28, which carries the secondgas chesk 30. The centres of the gas checks are connected by aperforated brass tube 32 which acts as the frangible tie and whichhouses an electrically-fired primer 38. The main charge (which isomitted from FIGURE 2 for clarity) lies in the space 36 around the tube.

The tube 32 can readily be made to exert a substantial degree ofconfinement to a good degree of accuracy. Moreover the breaking strengthof the tube can easily be adjusted by varying the size of theperforations. Consequently a good level of uniformity may be obtained inthe behaviour of successive rounds, which means that once the sights ofthe gun are set it will hit a target accurately.

The casing 28 has a rear cover 29 lightly soldered on, and includes aparachute 31 which is separated from the small shot 26 by a wad 33 andis connected to the front of the casing by a rod 35. On firing, thecasing bursts to release the small shot and is itself lowered harmlesslyby the parachute. Alternatively the casing may disintegrate. The shot isnot only retarded by air resistance, but also somewhat dispersed.

The passage of the casing and shot round the curve in the rear barreldoes not lead to any jamming or to appreciable erosion of the barrelwall. It seems probable therefore that the casing and the shot within itdeform somewhat in a ductile manner as they pass round the curve.

One lead 38 from the primer goes to the tube 32 and is thus connected,by contact of metallic parts, to the barrel of the gun, While the otherlead 40 goes to a contact ring 42 of metal foil mounted on a ring 44 ofinsulating material which fills a gap between the rims of the gaschecks. These rings disintegrate or are burnt away on firing. Thecontact ring engages a plunger 46 which extends through an insulatingbush 48 in the Wall of the chamber. The plunger and barrel are connectedto a magneto operated by squeezing a front part 50 of the handle 14.

The disintegration of the rings 42 and 44 means that there is nothing tobe extracted from the gun after firing. That is to say, the round isdevoid of anything in the nature of a cartridge case.

The chamber and front barrel can be disconnected from the rear barrelwhile remaining supported in a ring 51 carried by arms 52 and 54 of abracket extending forwards from the rear barrel. The rear of the chamberhas an external interrupted thread 58 in a socket 59 on the forward endof the rear barrel. Just in front of the thread the socket is enlargedand houses a U-sectioned flexible brass sealing ring 60, and a rigidguide ring 62. These cooperate with a cylindrical surface 64 on thechamber.

In loading, the front barrel and chamber, on being released from thesocket by a quarter turn, are slid forwards in the ring 51 until therear end of the chamber is clear of the socket, and then swung aboutpins 66 until the rear end of the chamber is sulficiently offset fromthe socket to permit a round to be inserted. The movements are thenreversed and the gun is ready to fire. A contact 68, on an insulatedmounting on the arm 54, makes con- ,tact with the outer end of theplunger 46 in the wall of the chamber when the front barrel and chamberare fully screwed home, thus completing the firing circuit from the lmagneto.

The plunger 46 is urged outwards by a light spring 70, so that it doesnot obstruct the barrel during loading. The contact 68 is urged inwardsby a stronger spring 72 which urges the plunger inwards against thecontact ring 42. When the gun is fired, the gas pressure forces theplunger outwards against the spring 72 until a conical part '74 sealsagainst a seat in the insulating bush 48 so that escape of gas isprevented.

The projectile, by reason of its favourable shape for air flow and itstail stabilizer, does not need a high velocity, but will travel in anearly flat trajectory with a relatively head of a kneeling man.Consequently the sole danger in rear of the gun is to a man standingupright directly behind the gun within 2 or 3 yards of the rear muzzle.

Guns and rounds according to the present invention may of course be madein a variety of sizes, but details of one typical example are givenbelow by way of illustration of the success achieved by the invention inmeeting the requirements for a truly satisfactory anti-tank gun:

Calibre of projectile 3.5 inch. Weight of projectile 5 lbs. 8 oz. Weightof spigot and gas check 1 lb. 7 oz.

Total 6 lbs. 15 oz.

Weight of shot including casing and gas check 6 lbs. 15 oz. Size of shotNo. 8. Material of easing Sheet metal or plastics. Thickness of casing.0l0-.0l5 inch. Weight of charge 29 grams. Material of charge Neoflak.Material of tie Brass. Minimum cross section of tie 0.2 sq. ins. Gaspressure to break tie 1.6 tons/sq. in. approx. Maximum gas pressureattained 3.5 tons/sq. in. approx. Length of round 2ft. 9 /2 ins. Lengthof front barrel 5 ft. 9ins. Length of rear barrel 6 ft. 2 ins. Radius ofcurvature of rear barrel 2 ft. 6 ins. approx. Angle of bend of rearbarrel 538 Total length of gun 11 ft. 9ins.

Total weight of gun without round lbs. Total weight of round 13 lbs. 10oz. Muzzle velocity of projectile 1,0001,200 ft./ sec. Muzzle energy ofprojectile 86,000 ft. lbs. approx. Range at 15 tangent elevation offront barrel 4,000 yards approx. Muzzle velocity of shot 1,000 ft./sec.approx. Range at which shot lands 300 yards approx.

The precise angle between the directions of discharge from the twobarrels is not critical. An obtuse angle in the range to 140 isconvenient, but angles nearer or nearer 90 are both possible.

It is essential for the bore of the rear barrel to be substantiallyuniform throughout its entire length. It is convenient, but notessential, for this bore to be the same size as the bore of the frontbarrel.

It is theoretically possible to have a rifled front barrel, and a rifledprojectile, but this is not usually desirable because a rifledprojectile would require a higher muzzle velocity, hence a largerpropellant charge, hence a heavier round, a stronger and thereforeheavier gun, and more conspicuous flash.

Although this invention is primarily concerned with anti-tank weapons,the same gun may be used to fire other projectiles for other purposes,for example anti-personnel projectiles.

Although the gun shown in the drawings is single-shot with hand loading,the invention may be embodied in guns with magazine loading andautomatic firing.

I claim:

1. A portable infantry gun, comprising: a first tubular member definingan elongate, open-ended passage having a straight axis and formingchamber and front barrel portions of the gun; a second tubular memberdefining an elongate, open-ended rear barrel passage for the gun andhaving a curvilinear axis the two extremities of which are inclined toone another at an obtuse angle of the order of 150 to 140, the rearbarrel passage having the same substantially uniform bore along itsentire length; and means so detachably engaging the chamber portion ofthe first tubular member with the second tubular member as to join thepassages with their axes in alignment at the joint and form a continuousopen-ended tube within the gun; and a unitary round loaded within thechamber portion of the gun, the round comprising a projectile of largemass relative to the mass of the gun; a cup-shaped gas check on the rearend of the projectile adapted to seal the front barrel portion; athin-walled casing containing a quantity of small shot and adapted topass along the curved rear barrel passage; a second cup-shaped gas checkon the forward end of the casing adapted to seal the rear barrelpassage; a propellant charge enclosed between the two gas checks,adapted when fired to propel the projectile from the front barrelportion with low muzzle velocity of the order of 1000 to 1200 feet persecond and to propel the casing and shot from the rear barrel passage,whereby, if the gun is adjacent the ground and the first tubular memberis substantially horizontal, the projectile travels in a nearly flatforward trajectory to each a target with substantial energy, and thesmall shot travels in a curved trajectory obliquely upwards and thendownwards to reach the ground with a non-lethal velocity, and the firingis accompanied by only very low emission of flash from the front barreland rear barrel; and means carried by the chamber portion for firing thepropellant charge.

2. For use with a unitary round of the type comprising a projectile oflarge mass relative to the mass of the gun, a cup-shaped gas check onthe rear end of the projectile, a thin-walled casing containing aquantity of small shot and adapted to pass rearwardly relative to theprojectile, a second cup-shaped gas check on the forward end of thecasing, and a propellant charge enclosed between the two gas checks,adapted when fired to propel the projectile with low muzzle velocity ofthe order of 1000 to 1200 feet per second and to propel the casing andshot rearwardly, a portable infantry gun, comprising: a first tubularmember defining an elongate, open-ended passage having a straight axisand forming chamber and front barrel portions of the gun; a secondsubular member defining an elongate, open-ended rear barrel passage forthe gun and having a curvilinear axis the two extremities of which areinclined to one another at an obtuse angle of the order of 150 to therear barrel passage having the same substantially uniform bore along itsentire length; and means so detachably engaging the chamber portion ofthe first tubular member with the second tubular member as to join thepassages with their axes in alignment at the joint and form a continuousopen-ended tube within the gun; and means carried by the chamber portionfor firing the propellant charge of a projectile, whereby, if the gun isadjacent the ground and the first tubular member is substantiallyhorizontal, the projectile travels in a nearly flat forward trajectoryto reach a target with substantial energy, and the small shot travels ina curved trajectory obliquely upwards and then downwards to reach theground with a non-lethal velocity, and the firing is accompanied by onlyvery low emission of flash from the front barrel and rear barrel.

References Cited in the file of this patent UNITED STATES PATENTS1,108,717 Davis Aug. 25, 1914 1,280,579 Stone et al. Oct. 1, 19181,394,490 Giles Oct. 18, 1921 2,466,714 Kroger et al Apr. 12, 19492,657,630 Blacker Nov. 3, 1953 FOREIGN PATENTS 590,268 Great BritainJuly 14, 1947

1. A PORTABLE INFANTRY GUN, COMPRISING: A FIRST TUBULAR MEMBER DEFININGAN ELONGATE, OPEN-ENDED PASSAGE HAVING A STRAIGHT AXIS AND FORMINGCHAMBER AND FRONT BARREL PORTIONS OF THE GUN; A SECOND TUBULAR MEMBERDEFINING AN ELONGATE, OPEN-ENDED REAR BARREL PASSAGE FOR THE GUN ANDHAVING A CURVILINEAR AXIS THE TWO EXTREMITIES OF WHICH ARE INCLINED TOONE ANOTHER AT AN OBTUSE ANGLE OF THE ORDER OF 150* TO 140*, THE REARBARREL PASSAGE HAVING THE SAME SUBSTANTIALLY UNIFORM BORE ALONG ITSENTIRE LENGTH; AND MEANS SO DETACHABLY ENGAGING THE CHAMBER PORTION OFTHE FIRST TUBULAR MEMBER WITH THE SECOND TUBULAR MEMBER AS TO JOIN THEPASSAGES WITH THEIR AXES IN ALIGNMENT AT THE JOINT AND FORM A CONTINUOUSOPEN-ENDED TUBE WITHIN THE GUN; AND A UNITARY ROUND LOADED WITHIN THECHAMBER PORTION OF THE GUN, THE ROUND COMPRISING A PROJECTILE OF LARGEMASS RELATIVE TO THE MASS OF THE GUN; A CUP-SHAPED GAS CHECK ON THE REAREND OF THE PROJECTILE ADAPTED TO SEAL THE FRONT BARREL PORTION; ATHIN-WALLED CASING CONTAINING A QUANTITY OF SMALL SHOT AND ADAPTED TOPASS ALONG THE CURVED REAR BARREL PASSAGE; A SECOND CUP-SHAPED GAS CHECKON THE FORWARD END OF THE CASING ADAPTED TO SEAL THE REAR BARRELPASSAGE; A PROPELLANT CHARGE ENCLOSED BETWEEN THE TWO GAS CHECKS,ADAPTED WHEN FIRED TO PROPEL THE PROJECTILE FROM THE FRONT BARRELPORTION WITH LOW MUZZLE VELOCITY OF THE ORDER OF 1000 TO 1200 FEET PERSECOND AND TO PROPEL THE CASING AND SHOT FROM THE REAR BARREL PASSAGE,WHEREBY, IF THE GUN IS ADJACENT THE GROUND AND THE FIRST TUBULAR MEMBERIS SUBSTANTIALLY HORIZONTAL, THE PROJECTILE TRAVELS IN A NEARLY FLATFORWARD TRAJECTORY TO EACH A TARGET WITH SUBSTANTIAL ENERGY, AND THESMALL SHOT TRAVELS IN A CURVED TRAJECTORY OBLIQUELY UPWARDS AND THENDOWNWARDS TO REACH THE GROUND WITH A NON-LETHAL VELOCITY, AND THE FIRINGIS ACCOMPANIED BY ONLY VERY LOW EMISSION OF FLASH FROM THE FRONT BARRELAND REAR BARREL; AND MEANS CARRIED BY THE CHAMBER PORTION FOR FIRING THEPROPELLANT CHARGE.